Iris-diaphragm.



A. WOLLENSAK.

IRI$ DIAPHRAGM. APPLICATION FILED MAR. 2, 1911.

Patented May 30, 1911.

UNITED snares PATENT onnion. Y

ANDREW WOLLENSAK, OF ROCHESTER, NEW YORK, ASSIGNOR T0 WOLLENSAK OPTICALCOMPANY, OF ROCHESTER, NEW YORK, A CORPORATION OF NEW YORK.

IRIS-DIAPHRAGM.

Specification of Letters Patent.

Patented May 30, 1911.

To all whom it may concern:

Be it known that I, ANDREW VVoLLnnsAK, a citizen of the United States,and resldent of Rochester, in the county of Monroe and.

State of New York, have invented certain new and useful Improvements inIris-Diaphragms, of which the following is a speclfication.

This application relates to improvements in iris-diaphragms such as areused in connection with cameras and other optical instruments. Adiaphragm of this type comprises a series of overlapping thin blades ofsheet-material, each blade being pivotally mounted at its ends in twoannular relatively-rotary members by which all of the blades are swungsimultaneously toward or from the center of the aperture.

In diaphragms of the type in question it is necessary to make the bladesof very thin, flexible, sheet-material, owing to their overlappingarrangement, in order that they may lie as nearly as possible in oneplane, and for this reason the blades are very easily distorted ortwisted at their ends by the means by which their movements areproduced. Furthermore, it has been found that the edges of the blades,where they cross each other, tend to catch against each other and resistmovement of the blades, and this resistance has a further tendency tocause the blades to be twisted or broken through the operation of theadjusting members.

The object of the present invention is to produce an iris-diaphragm inwhich the harmful twisting effect upon the blades is substantiallyeliminated, and the action of the blades rendered smooth and easy. Tothis end I employ a construction in which the ends of each blade areclosely embraced between two surfaces upon the annular supporting andcontrolling members of the diaphragm, so that the ends of the blades areeffectually prevented from twisting under the strains incurred in themovement of the blades. As a further precaution against twisting, and toproduce an easy sliding movement of the blades over each other, I modifythe usual crescent form of the blades by providing each blade withbifurcated ends, one extremity of each end constituting a bearing-lugcooperating with one of the annular members, while the other extremityextends beyond the bearing-lug and engages the surface of the adjacentblade,

and in this manner the blade, at each end, has a bearing upon theadjacent blade on each side of its pivotal connection with the annularmember. This bearing not only tends to prevent twisting action on theblade, but it also facilitates the movement of the edges of the bladesacross each other.

In the accompanying drawings :Figure 1 is a front-elevation of aniris-diaphragm embodying the present invention, mounted in ashutter-casing, and with parts broken away to illustrate theconstruction more fully; Fig. 2 is a section on the line 2-2 in Fig. 1,looking from beneath; Fig. 3 is a front-elevation of the rotarycontrollingmember; Fig. 4: is a front-elevation of the middle ring; andFig. 5 is a front-elevation of one of the blades.

The invention is applicable to iris-diaphragms of various forms, but inthe accompanying drawings it is illustrated as embodied in a diaphragmconstructed in accordance with United States Letters Patent issued toWollensak Optical Company, February 2S, 1911, No. 985,311. In thediaphragm of said patent the usual pivots projecting laterally from theblades are eliminated, and the blades are moved and supported by meansengaging them directly and in the planes of the blades.

The diaphragm is illustrated as inclosed within a shutter-casing havingthe usual cylindrical body-portion 6, flat back 7, and threaded nipple8.

Each blade of the diaphragm comprises a body-portion 9 of the usualcrescent shape. Each end of this blade is bifurcated, as shown in Fig.5, so as to produce, at the respective ends, two pivot-lugs 11 and 12and two tapering bearing-extremities 13. The pivot-lugs, in accordancewith said patent, are not provided with the usual metal pivots, but aremade in the form of fiat circular heads connected with the body of theblade by comparatively narrow necks.

The annular supporting and operating members comprise three rings 14, 15and 16, which are stamped from sheet-metal, and are hereinafterdesignated, respectively, as the back-ring, the middle-ring, and thefront-ring. The back-ring 14 is provided with a discontinuous, annularbead 17 producing a corresponding ridge on the front of the ring, andits outer margin 18 is also offset in the same direction, thus producingan annular groove 19 between the bead 17 and the margin 18. At equalintervals the back-ring is also provided with depressed portions orsockets 21, which interrupt the bead l7 and are of substantially thesame diameter as the pivot-lugs 12 on the blades. The back-ringconstitutes the rotatable member of the diaphragm, and it is providedwith the usual arm 22 which projects outwardly through an aperture 20 inthe casing and is manually operable to adjust the aperture of thediaphragm. The margin 18 of the back-ring is seated in an annular recess23 in the back 7 of the casing, as shown in Fig, 2. The middle-ring 15is provided with an annular bead 2 L, constituting a ridge on the rearsurface of the ring, and the inner margin of the ring is bent in theopposite direction to produce an annular ridge 28 on the front surfaceof the ring. This ring is fixed in the shutter-casing, be ing providedwith three lugs 25 adapted to receive screws for this purpose. Thefrontring, at its inner margin 26, is forwardly offset, as shown in Fig.2, and is provided with a series of apertures or sockets 27 extendingoutwardly from the portion 26 and of a diameter slightly greater thanthe diameter of the pivot-lugs 11 on the blades. The front-ring is fixedin the casing by means of screws 29 which also pass through the lugs 25on the middlering, and are threaded into the back 7 of the casing.

The blades are arranged in the usual overlapping position, as shown inFig. 1, each blade having its pivot-lug 11 located in one of theapertures 27 in the front-ring, and its pivot-lug 12 seated in one ofthe sockets 21 in the back-ring. The middle-ring 15 cooperates with theback-ring and the frontring to embrace the ends of the blades closely.The ridge 24-, being seated in the groove 19, confines the lugs 12 intheir sockets in a space of a depth equal only to the thickness of theblades, and the form of the pivot lugs and of the sockets is such thatthe blades have a swinging or pivotal movement in these sockets. In asimilar manner the pivot-lugs 11 are closely confined between the ridge28 and the rear surface of the frontring 16, in a space equal in depthonly to the thickness of the blade. The form of the sockets thusproduced is such as to permit the lugs 11 to have a longitudinal as wellas a pivotal movement, as is necessary for the free movement of theblades. By tightening the screws 29 more. or less, the parts may bedrawn together wit-h more or less pressure, and thus an adjustablefriction is secured by which the parts are maintained in adjustedposition, against accidental movement.

As shown in Fig. 1, each extremity 13 of each blade rests against theflat surface of the adjacent blade, so as to provide a bearing extendingin advance of the pivot-lug, and the blades are thus effectuallyprotected against twisting act-ion or against binding between the edgesof the blades.

My invention is not limited to the embodiment thereof hereinbeforedescribed and illustrated in the accompanying drawings, but may beembodied in various other forms within the nature of the invention, asit is defined in the following claims.

I claim 1. An iris-diaphragm having, in combination, tworelatively-rotary annular members, and a series of overlapping bladespivotally connected with, and actuated by, said members, each bladebeing a flat piece of thin sheet-material with a body-portion in thegeneral form of a crescent and with a pivotlug extending from its outeredge at each end, the extremities of the body-portion extending beyondthe pivot-lugs so as to provide a bearing between each blade and thecontiguous blade on both sides of each pivotlug.

2. An iris-diaphragm having, in combination, a series of overlappingblades of thin, flexible sheet-material, and annular means for adjustingand supporting the blades, said means being provided with a series ofsockets in each of which an extremity of one of the blades is seated andeach socket being of a depth substantially equal to the thickness of theblade, so that the blade is closely confined by the socket againsttwist-ing.

3. An iris-diaphragm having, in combina tion, a series of overlappingblades of thin, flexible sheet-material, and three superposed, annular,relatively-rotary adjusting and supporting members, each of the twoouter annular members embracing, between itself and the adjacent surfaceof the middle annular member, the respective extremities of the blades,whereby the blades are supported against twisting at both ends.

4. An iris-diaphragm having, in combination, a series of overlappingblades of thin, flexible sheet-material, and three superposed, annular,relatively-rotary adjusting and supporting members, the two outerannular members having each, at the surface adjacent the middle annularmember, a series of sockets to receive the respective extremities of theblades, and the middle annular member engaging the lateral surfaces ofsaid extremities opposite said sockets so as to confine the bladesclosely in the sockets.

5. An irisdiaphragm having, in combination, a series of overlappingblades of thin, flexible sheet-material, an annular adjusting memberhaving a series of sockets to receive, respectively, an extremity ofeach blade, and a second annular member having an annular ridge engagingsaid extremities opposite said sockets and confining them closelytherein.

6. An iris-diaphragm having, in combination, a series of overlappingblades of thin, ing and closely confining said extremities in flexiblesheet-material, an annular adjusting the sockets.

member having a series of sockets to receive,

respectively, an extremity of each blade, and ANDREW WOLLENSAK' 5 anannular groove connecting the sockets, Witnesses:

and a second annular member having an 2111- D. GURNEE,

nular ridge seated in the groove and engag- L. THON.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, I). G.

